To what extent does demotivation affect EFL learners’ English language proficiency attainment? The present study addresses this question by investigating the relationship between technological institute EFL students’ past demotivating factors and their English language proficiency. Although the role of demotivation in foreign language achievement has been examined, relatively few studies have been implemented to predict English language proficiency attainment from demotivating factors. Stepwise multiple regression analyses revealed that learning difficulties explained the most variance in the prediction of EFL learners’ English language proficiency while language-specific anxiety was found to be the second most significant predictor variable. Of learning difficulties, “bad at memorizing vocabulary” entered into both equations, demonstrating the issue of insufficient vocabulary inventory of Taiwanese EFL technological college students. Language-specific anxiety was considered to be interrelated with learners’ insufficient word bank in the present study.